Replace _mm_movemask_pi8 with the fallback_impl

This has to be done, because `_mm_movemask_pi8` got removed
from stdarch in rust-lang/stdarch#890

Author: Stupremee

src/codegen/reductions/mask/x86.rs

@@ -19,13 +19,7 @@ mod avx2;
 /// x86 64-bit m8x8 implementation
 macro_rules! x86_m8x8_impl {
     ($id:ident) => {
-        cfg_if! {
-            if #[cfg(all(target_arch = "x86_64", target_feature = "sse"))] {
-                x86_m8x8_sse_impl!($id);
-            } else {
-                fallback_impl!($id);
-            }
-        }
+        fallback_impl!($id);
     };
 }
 

src/lib.rs

@@ -209,7 +209,6 @@
     link_llvm_intrinsics,
     core_intrinsics,
     stmt_expr_attributes,
-    mmx_target_feature,
     crate_visibility_modifier,
     custom_inner_attributes
 )]